For versions 2018.1 and older (e.g. 10.5) tabcmd can be used on other machines: tabcmd

For version 2018.2 and newer tabcmd can be used on other machines: 2018.2 tabcmd

It is not mandatory to install it on the same machine as the Tableau Server, however, it won't hurt anything to do so. You can have it installed in multiple locations as there is no licensing limitation.